The instant invention relates to a device for the plucking of fibers from fiber bales by means of a plucking roller with teeth and capable of being moved back and forth, and by means of two toothed rollers, one of which is located before and one after the stripping roller, their axes being parallel to that of said stripping roller and which press down on the bale surface.
In a known device for the plucking of fiber bales, the fiber material is plucked from the forward face of a layered stack in form of a parallelepipedon by means of a plucking roller with needles which is supported on a sled travelling back and forth horizontally (DE-PS No. 1,193,844). The tearing out of large pieces from the layered stack is prevented by means of retention elements in form of corrugated rollers installed before and after the plucking roller in the manner of drag rollers and which are pressed against the forward surface. The retention force of such corrugated rollers is unsatisfactory however, especially when the fiber material is plucked from the bale from above.
It has, therefore, been proposed that a retention device be provided in form of a pivotably supported grate which can be pressed down on the bale surface, through which the needles or teeth of the plucking roller extend (DE-OS No. 2,847,461). The disadvantage is that during the plucking operation grooves and ridges are formed on the surface of the bale, requiring costly measures to be taken for their elimination. In this device two driven pressure rollers equipped with toothed rings are also provided, one before and one after the plucking roller, the axes of the pressure rollers being parallel to the axis of said stripping roller. These rollers, which press down on the surface of the bales, are intended to prevent the bale from tipping over during plucking, as the grate alone, generally does not suffice to prevent this. No improvement in fiber retention is achieved by means of these pressure rollers.